Fuel sender adjustment???

O

Oilslickwillie

Senior Member
Hello, I have searched the many posts here about fuel sender problems but did not find an answer to my particular problem. First let me say, the previous owner of my car did everything back-axx-wards and now I have the task to try and figure where he went wrong. I have a 55 Ford.
Note: I am not using the original fuel gauge, I am using a 12 volt gauge since the car is now 12 volt. I purchased a 12 volt sending unit from Mac's. I sat in the front seat while holding the new sender in my hands and wired the gauge + to the ignition hot. I wired the sender post on gauge to center post of sender unit. I grounded the gauge and the sender to a good ground. When I turn ignition on, the gauge reads a little over half a tank. Keep in mind, the sender is in my hand and the float is all the way down so I would think it should read empty. It's above half but when I lift the float rod upwards, it goes to full as it should. When I let it go it goes back to a little over half. Why not to empty. What am I missing. Seems easy to wire but not right. Any suggestions. Thanks.
 
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It's complicated.....
'55 Fords were 6volt. 56's were 12 volt and use actual 12v gauges.
'57+ are 12v but, use an underdash voltage regulator inline with 6v dash gauges.

Aftermarket parts can be 'oem style' or not, requiring an actual 12v or needing a voltage regulator.
Most new gauges and senders work best when bought together as a matched pair and installed following their instructions.

With some careful experimenting and a supply of fixed or variable resistors the gauge and sender you have might be able to work together.
Start by finding out how much more resistance / less voltage you need to get an 'empty' reading from the sender.

Don't ask about the Temperature sender & gauge, they can be even weirder if the heads have been changed.

.
 
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The sending units' ohm range must be coordinated with the gauge. Usually you can search for your gauge for sale to determine the ohm range of the sender needed.
 
I heard that the Ohm sender must meet the gauge sender.. My sender is 12 ohm so I need to find a 12 gauge for it to work right. Does this make sense.
 
The senders and gauges are usually rated in a range, such as 10-70 ohms. You can price gauges and senders and see which is your best option. If your gas gauge matches others in the car, you might want to match it. But you first have to identify what you have now, or buy a matched pair.
 
Pulled the gauge out of the car and will take it and the sender to O'Reilly Auto and have it checked. The gauge does not have a name on it. My sender will not work with SW gauges, at least that is what Mac's says. Will try to find a matched set I guess.
 
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